Spark-plug.



F. GERKEN,

SPARK PLUGr APPUc/mon FILED MN. l5, |917.

lm., Patented @11.15, 1918.

` FREDERICK GERKEN, `OF NEW YORK, N. Y.

SPARK-PLUG.

Massari.

Specification of Letters Patent. Patgntd Jan; 15, 191g .application filed January 15, 1917. Serial No. 142,335.

To'all whom it may concern.'

Be it known that I, FREDERICK GERKEN, a citizen of the United States of America, and

la. resident of New York, in the county of New York and State 4*of New- York, have invented certain new and useful Improvements -in Spark-Plugs, of which the followf ing is a specification.

My invention relates to improvements in 'so-.called spark plugs, that is to say,

" sparking devices employed for igiiiting the charges of internal combustion engines, and

.also employed, sometimes, in other connections.

lMy invention consists in a novel construction of the electrodes or sparking terminals of such plugs, whereby a very high efficiency of operation is obtained, and whereby detrimental collection of carbon deposits and the like on the terminalsl of the plug is avoided.

The object of my invention is to improve the eliciency of spark plugs of the type described, and to avoid the troubles heretofore experienced with spark plugs.

I will now proceedto describe myf invention with reference to the accompanying drawings,l and will then point out the'novel features in claims. .In said drawings:

Figure 1 shows a side elevation of my iinproved spark plug;

Fig. -2 shows an end view thereof, on a larger scale than Fig. 1';

Fig. 3 a detail elevation and partial vertical section of the lower portion of the spark plug; and

Fig. 4 a view similar to Fig. 2 showing an alternativefform of central electrode.

Y In the drawings, l'designates the outer "shell of thespark plug, provided, as usual,

with a threaded lower portion 2 adapted to 4be screwed into the usual spark-plug port The lower portion' ofA the the present day.

3designates one of the sparking terminals or electrodes of the plug; said terminal- 3 being a ring or annulus connected tothe portion 2 of theplug by strutsbr ligaments 4, there being, therefore, wide spaces 5 between the ring 3 andthe lower portion 2 of the shell.v i

6 designates the other sparking terminal or electrode of the plug, having the forni of a thin disk located within and spaced, as nearly as may be, uniformly away from the ring 3, and supported upon a central post 7.

' post 7.

It is to be understoodA that this post 7 is insulated in the usual manner from the shell l, 8 (Fig. l) designating a portion of the insulating material.; and that this post 7 is provided at its upper end with means, such asa screw nut 9, whereby one conductor of an electric circuit may be connected to said .I do not illustrate in detail the structure whereby the post 7 is insulated from the shell l, as such const ruction forms no portion of the present invention, and ordinary means for effecting such insulation may be employed.

As shown vin Fig. 2, the central electrode 6 is perforate; while as shown in Fig. l, that v'central electrode, there designated, by nul meral 6a, is imperforate.

Whether a erforate or imperforate centralelectrode be employed, depends to a large extent upon the conditions' obtaining in the engine in which the spark plug is used. It is found that if the engine be one having high compression and -employing battery ignition (both of which conditions tend to produce high temperatures of the spark plug terminals) it is better to use a perforate central electrode, such as'shown in Fig. 2; but if the engine in which the spark plug is used he one of moderate compression pressures, and one in which magneto ignition is used, a'n imperforate central electrode, such as shown in Fig. 4, may be employed to advantage.

Experience has shown that it isimportant that this central electrode G or 621 be thin. `A thickness of about .03 has been found to work well. If this central electrode be too thick carbon deposit will form upon it to a detrimental extent; otherwise, no such deposits will form. f

The form of the inner surface of the outer electrode 3 is important.' As shown in Fig. 2, the inner surface of the electrode 3 is of scalloped form; that is to say, grooves or notches 10, with intervening blunt' projecshown that the same engine, fitted with this spark plug, tends to develop 'materiallylnore power than when fitted with an ordinary spark plug the terminals of which are twoy or more sparking points of ordinary con-V struction. It has been found impossible in practice to .foul the spark terminals of this plug with carbon deposits, formed in the operation of the engine; carbonsimply does not deposit, or, at least, does not remain deposited on the sparking terminals 3 and 6 to Vsuch an extent as to cause fouling, orto interfere with the operationof the englne. It appears that the grooves 1-0 A in the inner surface ofthe outer sparking terminal, and very likelythe openings-l2 in" the central electrode, have much to do with the prevention of formation of Inaterial carbon deposits on these terminals. It appears that the portion of the charge which, during the compression stroke, col'- lects in lthe chamber within the portion 2 of v the plug, and then, upon ignition, blows out past .the sparking terminals 3 and 6, passes'as jets through the notches 10,v clearing the sparki-ng'terminals of the plug; and

sion, battery-ignition engine, the perforated central electrode 6 does not cause preignition, whereas the solid central electrode 6n shown in Fig. 4, may, in such engine, cause preignitlon; though the form shown 1n F 1g. 4` w1ll not cause .prelgnition 1n an engine of a type lwith which itis intended to be used.

Furthermore, it has been found that engines fitted with spark plugs such asshown herein, start more readily and more quickly,

under conditions which normally cause'dificult starting, than when the ordinary pointed spark plugs are used. So true is this, that it has been found that engines fitted with this spark plugv will run very satisfactorily on kerosene, and without produc'ing smoke, such engines being merely started on gasolene and then immediately switched over to theluse of kerosene, and this without any heating up run on gasolene.

It seems to` be important that the inner electrode 6 shall be within the outer-electrode 3, and notoutside thereof, .as has-been lthe case in some prior spark plugs. Also, it seems to loeimportant that the outer elecf ing van'- trode lshall not be a tube continuous with the portion 2 of the spark plug; the separation of `the terminal 3 from the tubular-'portion necting ligaments 4) so that openings A5 are existent-between portions 2 and 3 of the plug, seems to be essential.

vIt has also been-y found ythat, when using.

this spark plug, a leaner mixture may be used in the engine than when ordinary spark -plugs are used. This resultsin great economy in the use of fuel.

the plug of-the patent to Walter No. 812,622, and embodies improvements over that v2of the spark plug (except for the con- 75 This spark plugis an improvement upon Walter plug which have been found to be importantl in practice and to improved results. 4

What I claim-is:-

1. In .a spark plug, the combination with a shell, having within it a pocket and carryouter ring-like spark-terminal give greatly I grooved interiorlyl and supported by but ,denced by the fact that, in a high compresl scribing witnesses. l

spaced away from such shellby connecting. ligaments providing openingsbetween the main portion ofthe shell and the said ring terminal, of another spark terminal within' said ring terminal but spaced away therefrom' and suitably supported,- -and havingv the form lof a thin disk.4

2.1In a spark plug, the combination with a shell, having within it a pocket and carry-4 ing an outer ring-like Spark-terminal grooved interiorly andsupported by VVVbut spaced away. from such shell by connected ligaments providing 4openings between the main portionv of the shell and the said ring terminal, of another spark terminal within said ring terminal but spaced away therefrom and suitably supported, and having the form. of athin disk, said disk being perforate.' i 1 3. A spark plug provided with two spark-- terminals, oneof which is a ring and` the other of which is a thin disk located within that ring, said ring having an interior scalloped surface.

4. Aspark tionand two spark-terminals supported therefrom and insulated one from theother.

one of said terminals being` a ring spacec.v

away from the body of -the plug andhaving a scalloped interior surface, the other, of

said terminals being a thin disk'locatzedl within said ring. h

In testimonywhereofI have slgned this specification in the presence of two subi FREDERICK GERKEN. Witnesses;

JOSEPH L. Ecran, PAUL- H.- FRANKE.,

plug comprising a body porn 

